Day 34: Board Meeting, CAPM Practical, & Freezing Acid

October 25, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Board Meeting

We had a board meeting to wrap up the buggy lab. A lot of students who are normally quiet in whole class discussions spoke up today, which was great. In addition, there were some interesting observations that don’t always come up, like the student who commented the intercept did not depend on the slope. At the end of the hour, I also asked groups to whiteboard a CER for what the momentum vs. time graph should look like and, while we didn’t have a chance to discuss the boards, groups consistently were on the right track and not only connected the buggy lab to the definition of momentum, but to Newton’s 1st Law by discussing whether they could identify unbalanced forces on the buggy.

Physics: CAPM Practical

Students started working on a constant acceleration lab practical where they try to get a marble rolling down a ramp to land in a cup attached to a moving buggy. Some groups got a starting position for the marble while others got a starting position for the buggy. A lot of groups had trouble focusing on individual pieces of the task; tomorrow, I may take a few minutes to talk through the major steps students need to take. I’m also seeing students continue to struggle with confidence; they are nailing the problems, but just don’t believe that they get it, which makes it difficult to approach a challenging lab practical.

Chemistry Essentials: Freezing Acid

We discussed the results of yesterday’s lab. At the end of the hour yesterday, a lot of students didn’t seem convinced that temperature stays constant during a phase change, partly because they were focusing on their data tables and saw very small temperature variations. Today, I projected a graph from one of the groups for the discussion, and students saw much more clearly that the temperature is pretty constant. When students graph in Desmos, I usually allow one group member to make a graph as long as everyone sketches it (I don’t have a good way for students to print), but I think that’s making it too easy for most of the group to just glance at the graph so I need to work on ways to get students looking closer. I usually have a handout for labs in this course, so I’ll probably add some questions to prompt students to look carefully at their group’s graph to the next lab to see if that helps.

Day 33: Buggies, Problems, & Freezing Acid

October 24, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Buggies

Students collected data to produce position vs. time graphs for a buggy travelling at a constant speed. While I really like this lab for the start of the year, it was fun to see a group that has a pretty strong class culture and is developing some good skills tackles a fairly easy lab like this one. My students were also SUPER excited about the buggies; I don’t think I’ve ever had students who were so into them.

Physics: CAPM Problems

Students worked on another problem set to practice constant acceleration. We’re at a point where a lot of students are getting it and just doing more problems won’t get them there, so its time to move on.

Chemistry Essentials: Freezing Acid

Students made temperature vs. time graphs for freezing lauric acid. A lot of students are still not convinced that the temperature stays constant during a phase change, so I’ll need to make sure we spend some time going over the graphs tomorrow.

Day 32: Whiteboarding Galore

October 23, 2017October 23, 2017 / Marta R. Stoeckel / Leave a comment

Between having a sub on Wednesday and no school on Thursday or Friday, today was all about getting my classes back on track.

AP Physics: Conservation of Momentum Problems

Students whiteboarded the conservation of momentum problems from last Tuesday. Many of the problems require students to shift between thinking about the system as a whole and thinking about individual objects, and interaction diagrams (or system schema) proved to be incredibly powerful tools. The first year I used the Modeling Instruction curriculum, I didn’t quite get them and, as a result, my students never really saw the value, but my students and I are now huge fans.

Physics: Constant Acceleration Problems

On Wednesday, I left my students some problems that included several that started with graphs they’d already sketched and annotated. My students admitted that they made very little progress on Wednesday, partly because they got confused and shut down. This has been pretty common with my students this year, so we spent some time discussing alternative strategies for when they are stuck. Afterward, students whiteboarded the problems for a gallery walk. They are making good progress on connecting the features of the graph to the physical meaning it represents.

Chemistry Essentials: Phase Change Bar Charts

On Wednesday, students watched a short video lecture where I talked about the results of Tuesday’s phase change lab and introduced energy bar charts. While students got nice graphs from the lab, they were confused by the video lecture, so we spent most of the hour discussing it. It turns out the main issue is we haven’t spent much time on what the particles are doing during a phase change, so they weren’t willing to accept that explanation for the constant temperature in the lab without some additional convincing. I fired up a PhET simulation, which seemed to fill in some of the necessary gaps and allowed students to take a much more successful second shot at Wednesday’s bar chart problems.

Day 31: Multiple Choice, Problems, & Bar Charts

October 18, 2017October 17, 2017 / Marta R. Stoeckel / 1 Comment

I was home sick today, so wasn’t able to take any photos.

AP Physics: Multiple Choice

Students worked on some multiple choice problems off practice AP exams. I usually have students answer individually with Plickers, then talk to each other and answer again before we have some whole-class discussion. To try and replicate that, I gave students two spaces to answer the questions so they can do all of them individually, then talk about each one with their group. I put in my notes to have some whole-class discussion about the answers at the end, which I’ll be curious to hear how it goes.

Physics: Problems

Students took the plunge to start calculations with constant acceleration. As part of their worksheet annotating graphs, I had students sketch and annotate v-t graphs given just the statement part of some of today’s problems. I’ll be curious to see if that is a useful bridge.

Chemistry Essentials: Bar Charts

Students worked on some bar charts for objects heating up and going through phase changes. We ran out of time to discuss the lab, so I ended up recording a video lecture that gives away the big ideas from the lab.

Day 30: Problems, Annotating Graphs, & Boiling Ice

October 17, 2017 / Marta R. Stoeckel / 1 Comment

AP Physics: Problems

Students worked on some conservation of momentum problems. When students asked for help, I could tell pretty quickly who had sketched interaction diagrams. Especially now that I’m embedding center of mass, they have become an incredibly powerful tool. I also demonstrated exploding carts on a balanced track and was pleased at how easily students used the center of mass of the system to explain why it stayed balanced, even when the carts had different masses.

Physics: Annotating Graphs

Students whiteboarded their solutions to yesterday’s problems. I’m pleased to see a lot of students starting to make sense of the physical meaning of the graphs. I was surprised by some students who struggled to differentiate between initial velocity and maximum velocity, but I think they were able to clear up their confusion by the end of the hour.

graph soln

Chemistry Essentials: Boiling Ice

Students recorded temperatures as ice melted and eventually boiled. A lot of students where quick to say their results didn’t make sense when they saw minimal temperature changes during the phase changes, which was great.

ice melting.jpg

Day 29: Conservation of Momentum, Annotating Graphs, & Temperature vs. Heat

October 16, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Conservation of Momentum

We had a board meeting on last week’s conservation of momentum lab. As part of their whiteboards, I asked students to write a CER on whether their results made sense and encouraged them to use Newton’s Laws in their thinking. The 1st Law was a much more popular approach than the 3rd Law, but I was pleased at the connections were making.

ap cons.jpg

Physics: Annotating Graphs

Students started working on some problems to annotate velocity vs. time graphs and write equations for the area. I think this is helping some of my students to make more connections to what the graph actually represents, which will be an important stepping stone to solving problems. I also added some problems that just ask students to sketch and annotate a v-t graph from the kind of written description that would start a problem.

phys anno

Chemistry Essentials: Temperature vs. Heat

We took some notes on heat and temperature, then I asked students to predict whether there would be a larger temperature change when I added a small amount of boiling water or a large amount of warm water to a large beaker of room temperature water. Students seemed to wrap their heads around the difference and were able to explain why the warm water produced a bigger temperature change after the demo.

chem temp.jpg

Day 28: Conservation of Momentum, Mistakes Game, & Measurement

October 13, 2017October 13, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Collisions

After their quiz, students wrapped up the data collection on the collisions lab. Things went very smoothly, and a lot of groups have already commented on the pattern in their momentums. This is one of the times I love having quantitative uncertainty in the course, because students are independently deciding whether their momentums are close or effectively equal.

Physics: Mistakes Game

Students played the mistakes game with stacks of kinematic graphs. In class discussions, I’ve been struggling to get students to speak up and it is usually one or two students who do most of the talking after lots of long silences. Today, one of those students asked a question about the a vs. t graph, a member of the group presenting said, without any shame or fear, “We don’t really understand those graphs, so we just drew something.” All of the sudden, the whole class was animated and students who are normally quiet, even in small groups, were jumping in with fantastic questions. It was a fantastic way to end the week with that class.

Chemistry Essentials: Measurement

When I gave some notes on temperature scales yesterday, I had a student ask whether Kelvin is a more accurate scale than Fahrenheit and several others questioned it when I said 98.6 rounds to 100. I’m really excited about the thinking about measurement this shows, so I decided to lean in and do a Modeling Instruction measurement lab I’d skipped during the first unit. I had students measure the lab tables with popsicle sticks, gradually adding marks to make them more accurate. Next time, I think I will have them measure a bigger mix of objects, including some shorter than their tool.

Day 27: Collisions, Graph Stacks, & Linked Balloons

October 12, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Collisions

Students started collecting data for the momentum before and after a series of different collisions to discover conservation of momentum. Several groups had a lot of trouble with what we meant by before or after the collision, which showed up as trouble both in filling out the table I gave them and in seeing how to place the carts and photogates appropriately. I wonder if having students draw an SOS diagram for the first collision would have helped with that.

Physics: Graph Stacks

We used the motion encoder to check the graphs students drew for objects on ramps earlier this week. Afterward, students started working on translating between our different representations for accelerated motion. A lot of my conversations with students today have me thinking that many of them are memorizing shapes of graphs without understanding what they represent. I need to keep working on ways to help students attach meaning to the shapes.

Chemistry Essentials: Pressure

I put a large balloon and a small one on opposite ends of a PVC pipe, using alligator clips to close both. Students sketched particle diagrams to predict what should happen when I removed the clips; I wish I’d had them write CERs instead to encourage more interpretation of the particle diagrams. After I showed students both balloons stays the same size, I had them do a second round of particle diagrams to explain why. There was some great conversation about pressure, but I think that phase also would have been better served with a CER.

Day 25: Center of Mass, Board Meeting, & Gas Laws

October 10, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Center of Mass

Students continued yesterday’s video analysis, based on the article by Taylor Kaar, Linda Pollack, Michael Lerner, and Robert Engles in The Physics Teacher. Today, students analyzed the motion of four hover disks linked into a square from several different perspectives. They were a little bothered that it was tricky to spot the center of the square, but I like that we’ll be able to have a conversation about whether there has to be any mass at the center of mass.

Physics: Board Meeting

Students whiteboarded their results from the video analysis the last few days. Framing this around a CER with a more specific question than usual had the desired effect and I saw students keeping much more complete records than usual. Students are continuing to struggle with recognizing the physical meaning of features on the graph, so I need to keep giving students opportunities to work on that.

Chemistry Essentials: Gas Laws Simulation

Students used the PhET Gas Properties simulation to take quantitative data for the ideal gas laws. I think the class would have benefited from a little more discussion prior to using the simulation to set up what we were measuring and why, rather than just giving them an assignment in Google Classroom that told them what to measure. However, students were very successful in recognizing the quantitative relationships I wanted them to see.

Day 24: Center of Mass, Ramps, & Gas Laws

October 9, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Center of Mass

Students started a video analysis activity by Taylor Kaar, Linda Pollack, Michael Lerner, and Robert Engles that recently appeared in The Physics Teacher. I gave students a video of two linked hover disks and had students first track one of the disks, then track the center of mass for the system. In their article, the authors say their students resist tracking the disks, wanting to jump straight to the center of mass. My students, however, were very happy to track the motion of the disks, which made for a really satisfying payoff when they saw how much simpler the motion of the center of mass is.

Linked hover disks; from video by Kaar, Pollack, Lerner, & Engles

x vs. t for disk (red) and CoM (green)

Physics: Ramps

I’ve found a lot of groups are recording pretty incomplete data during labs. I think since groups don’t make much use of their individual results, some of these students aren’t seeing the value in recording that information. To give them a little more purpose, today we had some discussion to identify changes that could affect the motion of a hover disk on a ramp, then tasked them with collecting data to write a CER to answer how the change affects the motion. This will hit some points I wanted to get anyway, while also giving each group their own task using their data.

Chemistry Essentials: Gas Laws

Students made qualitative observations using sealed syringes in water baths. The ice machine in the school is broken, so the cold water tests didn’t work out very well, but we got some great results with hot water. A few groups had some trouble distinguishing between a change in pressure and a change in volume, so I wish we’d spent some time discussing how we could tell when the pressure in the syringe went up prior to the lab. However, by the end of the hour, groups were able to come up with qualitative descriptions of the ideal gas laws.